It has not been an easy season for a pair of first-year head coaches who will be on opposing sidelines when the Arizona Cardinals host the Detroit Lions on Sunday afternoon.

While the Lions (4-8) remain mathematically alive in the NFC postseason chase, they have been a huge disappointment under head coach Matt Patricia, who was hired away from the New England Patriots after Jim Caldwell was dismissed despite guiding the team to back-to-back 9-7 seasons.

The outlook is just as bleak in the desert. The Cardinals (3-9) brought in former Carolina Panthers defensive coordinator Steve Wilks following the offseason retirement of head coach Bruce Arians, but two of their three wins have come against the last-place San Francisco 49ers.

Arizona does have something to build upon after springing a 20-17 upset at Green Bay last week, a result that prompted the Packers to fire longtime head coach Mike McCarthy.

However, the Cardinals will limp into Sunday's matchup against Detroit. Their decimated offensive line saw left tackle D.J. Humphries become the sixth member of the unit to go on injured reserve due to an ailing right knee that has hindered him for the past month.

"We can't worry about what we don't have," Wilks said. "We've got to go play a football game."

Rookie center Mason Cole has started all 12 games this season after Shipley was injured early in training camp. He's the only one left that saw any action since Week 1. Arizona's new line consists of three rookies in Cole, left tackle Korey Cunningham and left guard Colby Gossett. The new right tackle is second-year pro Will Holden, who signed with the team last week.

"I think it's really just a matter of trying to find some consistency and staying the course," said Oday Aboushi, a six-year veteran who has replaced Pugh at right guard. "I know a lot of the guys are first-year guys in there and we're still jelling, but as the group goes, we're just going to try to continue to get better and continue to work on things we've been working on."

That line will get a stiff test against an improving Detroit defensive front that's quietly become a strength throughout the season. The Lions fortified their defensive line in October when they traded a fifth-round draft pick to the New York Giants for nose tackle Damon Harrison.

Harrison, at 6-foot-3 and 350-plus pounds, has played at a Pro Bowl level since arriving in Detroit. He has 31 tackles, 3.5 sacks and one forced fumble in six games and, more important, has helped bring out the best in emerging young tackles A'Shawn Robinson and Da'Shawn Hand.

"(He's) really been very healthy for that room and has really kind of helped that unit grow quite a bit," Patricia said. "And some of the things that we talked about; as far as some of the improvement that we've seen has really been attributed to some of that stuff on the front with those guys on the D-line and the linebackers and kind of that unit working together.

"So I just think he's been great. I think we've obviously got a long way to go and all that, but for a guy in that situation, it's never easy and I think he's done a great job."

Both teams have lost a key first-year player on the other side of the ball. Rookie running back Kerryon Johnson, Detroit's leading rusher with 641 yards, has missed the past two games with a knee injury and there is no timetable for his return. LeGarrette Blount rushed for 149 yards and two touchdowns the last two weeks.

"They're just day-to-day with it and trying to evaluate our players as they're trying to work themselves back into a situation where they can go help us and go compete," said Patricia of Johnson's status.

Arizona wide receiver Christian Kirk, also a second-round pick in this year's draft and the team leader in receiving yards, suffered a broken foot in last weekend's win and was placed on injured reserve.

"It's a big bummer," rookie quarterback Josh Rosen said. "It's a bummer for the Cardinals and everything, but for him as well because he was starting to hit his stride. He was starting to really feel comfortable out there, and we were getting that connection. Sometimes a play here or there, regardless of coverage, this is my guy on this particular situation."